Aniline → N-(1-Boc-piperidin-3-ylmethyl)aniline

Participants

Reaction Steps

To a solution of N-Boc-piperidin-3-yl-formaldehyde 3 (5.20 g, 24.4 mmol) in 50 mL of dry methanol and 50 mL of trimethylorthoformate was added aniline (2.50 g, 1.1 eq.), and the mixture was stirred at room temperature for 30 minutes. NaBH3CN (95%, 1.84 g, 1.1 eq.) was introduced in one portion, and the mixture was stirred at room temperature overnight. The mixture was quenched with 30 mL of aqueous potassium carbonate (sat.), then extracted with ethyl acetate (3×100 mL). The extracts were combined and washed with aqueous NaHCO3 (sat., 2×50 mL), brine (50 mL), and dried over anhydrous sodium sulfate. After the solvent was removed, the remaining oily residue was purified by a flash column chromatography (silica gel, hexane:ethyl acetate (1:1) to afford N-(1-Boc-piperidin-3-ylmethyl)-aniline 4 as white solid (5.60 g, 79%). IR (film, cm−1) 3520, 3263, 3004, 2976, 2932, 2854, 1688, 1589, 1521, 1482, 1422, 1365, 1267, 1243, 1175, 1150, 794, 709; 1H NMR (CDCl3, ppm) 7.20 (t, 2H, J=7.8 Hz), 6.72 (t, 1H, J=6.8 Hz), 6.63 (d, 2H, J=8.3 Hz), 4.00-3.78 (m, 3H), 3.07-2.70 (m, 4H), 2.00-1.20 (m, 5H), 1.48 (s, overlap, 9H).

Provenance & Evidence